Will any phone number work? How do I get a verification number?

Related Questions: I don't have a phone number, can I still use signal? Will it work if I have an iPad or iPod?

Android Users, see information here. iOS Users, continue below.

A number can only be registered to one device at a time. Think of your phone number as your username or user id. 

As long as you can receive SMS to your device or receive a phone call, then you will be able to verify your device and use it. 

After you download the app, you will be asked to input your phone number.  Your phone number can be your

1. Mobile device number
2. Google Voice number
3. Any VoIP number
4. Landline number

If your phone number is listed in numbers 2-4 above, for any Signal message or Signal call your recipient will see the Signal registered number of your Google Voice, VoiP or Landline number.  

SMS Verification Number
After you input your number, the system will send you a verification SMS. iPhone users can tap on the link or input the 6-digit verification code directly into the app. 

Call Verification Number
If the SMS verification fails the verification code will be delivered to you by a phone call. Signal users on an iPad or iPod touch can expect to need a verification number via a call.  Please be ready to write down or remember the 6-digit verification code.